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href="/vdoing-demo-repository/pages/ceea69/#_01-函数的快速体验" class="sidebar-link">01. 函数的快速体验</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_1-1-快速体验" class="sidebar-link">1.1 快速体验</a></li></ul></li><li class="sidebar-sub-header level2"><a href="/vdoing-demo-repository/pages/ceea69/#_02-函数基本使用" class="sidebar-link">02. 函数基本使用</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_2-1-函数的定义" class="sidebar-link">2.1 函数的定义</a></li><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_2-2-函数调用" class="sidebar-link">2.2 函数调用</a></li><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_2-3-第一个函数演练" class="sidebar-link">2.3 第一个函数演练</a></li><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_2-4-pycharm-的调试工具" class="sidebar-link">2.4 PyCharm 的调试工具</a></li><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_2-5-函数的文档注释" class="sidebar-link">2.5 函数的文档注释</a></li></ul></li><li class="sidebar-sub-header level2"><a href="/vdoing-demo-repository/pages/ceea69/#_03-函数的参数" class="sidebar-link">03. 函数的参数</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_3-1-函数参数的使用" class="sidebar-link">3.1 函数参数的使用</a></li><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_3-2-参数的作用" class="sidebar-link">3.2 参数的作用</a></li><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_3-3-形参和实参" class="sidebar-link">3.3 形参和实参</a></li></ul></li><li class="sidebar-sub-header level2"><a href="/vdoing-demo-repository/pages/ceea69/#_04-函数的返回值" class="sidebar-link">04. 函数的返回值</a></li><li class="sidebar-sub-header level2"><a href="/vdoing-demo-repository/pages/ceea69/#_05-函数的嵌套调用" class="sidebar-link">05. 函数的嵌套调用</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#函数嵌套的演练-打印分隔线" class="sidebar-link">函数嵌套的演练 —— 打印分隔线</a></li></ul></li><li class="sidebar-sub-header level2"><a href="/vdoing-demo-repository/pages/ceea69/#_06-使用模块中的函数" class="sidebar-link">06. 使用模块中的函数</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_6-1-第一个模块体验" class="sidebar-link">6.1 第一个模块体验</a></li><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_6-2-模块名也是一个标识符" class="sidebar-link">6.2 模块名也是一个标识符</a></li><li class="sidebar-sub-header level3"><a href="/vdoing-demo-repository/pages/ceea69/#_6-3-pyc-文件-了解" class="sidebar-link">6.3 Pyc 文件（了解）</a></li></ul></li></ul></li><li><a href="/vdoing-demo-repository/pages/e158a8/" class="sidebar-link">14_高级变量类型</a></li><li><a href="/vdoing-demo-repository/pages/ed6fdd/" class="sidebar-link">15_名片管理系统(综合应用)</a></li><li><a href="/vdoing-demo-repository/pages/e98ba6/" class="sidebar-link">16_变量进阶(理解)</a></li><li><a href="/vdoing-demo-repository/pages/f99095/" class="sidebar-link">17_函数进阶</a></li></ul> </aside> <div><main class="page"><div class="theme-vdoing-wrapper "><div class="articleInfo-wrap" data-v-06225672><div class="articleInfo" data-v-06225672><ul class="breadcrumbs" data-v-06225672><li data-v-06225672><a href="/vdoing-demo-repository/" title="首页" class="iconfont icon-home router-link-active" data-v-06225672></a></li> <li data-v-06225672><a href="/vdoing-demo-repository/python/#Python" data-v-06225672>Python</a></li></ul> <div class="info" data-v-06225672><!----> <div title="创建时间" class="date iconfont icon-riqi" data-v-06225672><a href="javascript:;" data-v-06225672>2023-04-02</a></div> <!----></div></div></div> <!----> <div class="content-wrapper"><div class="right-menu-wrapper"><div class="right-menu-margin"><div class="right-menu-title">目录</div> <div class="right-menu-content"></div></div></div> <h1><img src="">13_函数基础<!----></h1> <!----> <div class="theme-vdoing-content content__default"><h1 id="函数基础"><a href="#函数基础" class="header-anchor">#</a> 函数基础</h1> <h2 id="目标"><a href="#目标" class="header-anchor">#</a> 目标</h2> <ul><li>函数的快速体验</li> <li>函数的基本使用</li> <li>函数的参数</li> <li>函数的返回值</li> <li>函数的嵌套调用</li> <li>在模块中定义函数</li></ul> <h2 id="_01-函数的快速体验"><a href="#_01-函数的快速体验" class="header-anchor">#</a> 01. 函数的快速体验</h2> <h3 id="_1-1-快速体验"><a href="#_1-1-快速体验" class="header-anchor">#</a> 1.1 快速体验</h3> <ul><li>所谓<strong>函数</strong>，就是把 <strong>具有独立功能的代码块</strong> 组织为一个小模块，在需要的时候 <strong>调用</strong></li> <li>函数的使用包含两个步骤：
<ol><li>定义函数 —— <strong>封装</strong> 独立的功能</li> <li>调用函数 —— 享受 <strong>封装</strong> 的成果</li></ol></li> <li><strong>函数的作用</strong>，在开发程序时，使用函数可以提高编写的效率以及代码的 <strong>重用</strong></li></ul> <p><strong>演练步骤</strong></p> <ol><li>新建 <code>04_函数</code> 项目</li> <li>复制之前完成的 <strong>乘法表</strong> 文件</li> <li>修改文件，增加函数定义 <code>multiple_table():</code></li> <li>新建另外一个文件，使用 <code>import</code> 导入并且调用函数</li></ol> <h2 id="_02-函数基本使用"><a href="#_02-函数基本使用" class="header-anchor">#</a> 02. 函数基本使用</h2> <h3 id="_2-1-函数的定义"><a href="#_2-1-函数的定义" class="header-anchor">#</a> 2.1 函数的定义</h3> <p>定义函数的格式如下：</p> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> 函数名<span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">:</span>

    函数封装的代码
    ……
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br></div></div><ol><li><code>def</code> 是英文 <code>define</code> 的缩写</li> <li><strong>函数名称</strong> 应该能够表达 <strong>函数封装代码</strong> 的功能，方便后续的调用</li> <li><strong>函数名称</strong> 的命名应该 <strong>符合</strong> <strong>标识符的命名规则</strong> <ul><li>可以由 <strong>字母</strong>、<strong>下划线</strong> 和 <strong>数字</strong> 组成</li> <li><strong>不能以数字开头</strong></li> <li><strong>不能与关键字重名</strong></li></ul></li></ol> <h3 id="_2-2-函数调用"><a href="#_2-2-函数调用" class="header-anchor">#</a> 2.2 函数调用</h3> <p>调用函数很简单的，通过 <code>函数名()</code> 即可完成对函数的调用</p> <h3 id="_2-3-第一个函数演练"><a href="#_2-3-第一个函数演练" class="header-anchor">#</a> 2.3 第一个函数演练</h3> <p><strong>需求</strong></p> <ul><li><ol><li>编写一个打招呼 <code>say_hello</code> 的函数，封装三行打招呼的代码</li></ol></li> <li><ol start="2"><li>在函数下方调用打招呼的代码</li></ol></li></ul> <div class="language-python line-numbers-mode"><pre class="language-python"><code>name <span class="token operator">=</span> <span class="token string">&quot;小明&quot;</span>


<span class="token comment"># 解释器知道这里定义了一个函数</span>
<span class="token keyword">def</span> <span class="token function">say_hello</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">:</span>
    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;hello 1&quot;</span><span class="token punctuation">)</span>
    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;hello 2&quot;</span><span class="token punctuation">)</span>
    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;hello 3&quot;</span><span class="token punctuation">)</span>

<span class="token keyword">print</span><span class="token punctuation">(</span>name<span class="token punctuation">)</span>
<span class="token comment"># 只有在调用函数时，之前定义的函数才会被执行</span>
<span class="token comment"># 函数执行完成之后，会重新回到之前的程序中，继续执行后续的代码</span>
say_hello<span class="token punctuation">(</span><span class="token punctuation">)</span>

<span class="token keyword">print</span><span class="token punctuation">(</span>name<span class="token punctuation">)</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br></div></div><blockquote><p>用 <strong>单步执行 F8 和 F7</strong> 观察以下代码的执行过程</p></blockquote> <ul><li>定义好函数之后，只表示这个函数封装了一段代码而已</li> <li>如果不主动调用函数，函数是不会主动执行的</li></ul> <h4 id="思考"><a href="#思考" class="header-anchor">#</a> 思考</h4> <ul><li><p>能否将 <strong>函数调用</strong> 放在 <strong>函数定义</strong> 的上方？</p> <ul><li>不能！</li> <li>因为在 <strong>使用函数名</strong> 调用函数之前，必须要保证 <code>Python</code> 已经知道函数的存在</li> <li>否则控制台会提示 <code>NameError: name 'say_hello' is not defined</code> (<strong>名称错误：say_hello 这个名字没有被定义</strong>)</li></ul></li></ul> <h3 id="_2-4-pycharm-的调试工具"><a href="#_2-4-pycharm-的调试工具" class="header-anchor">#</a> 2.4 PyCharm 的调试工具</h3> <ul><li><strong>F8 Step Over</strong> 可以单步执行代码，会把函数调用看作是一行代码直接执行</li> <li><strong>F7 Step Into</strong> 可以单步执行代码，如果是函数，会进入函数内部</li></ul> <h3 id="_2-5-函数的文档注释"><a href="#_2-5-函数的文档注释" class="header-anchor">#</a> 2.5 函数的文档注释</h3> <ul><li>在开发中，如果希望给函数添加注释，应该在 <strong>定义函数</strong> 的下方，使用 <strong>连续的三对引号</strong></li> <li>在 <strong>连续的三对引号</strong> 之间编写对函数的说明文字</li> <li>在 <strong>函数调用</strong> 位置，使用快捷键 <code>CTRL + Q</code> 可以查看函数的说明信息</li></ul> <blockquote><p>注意：因为 <strong>函数体相对比较独立</strong>，<strong>函数定义的上方</strong>，应该和其他代码（包括注释）保留 <strong>两个空行</strong></p></blockquote> <h2 id="_03-函数的参数"><a href="#_03-函数的参数" class="header-anchor">#</a> 03. 函数的参数</h2> <p><strong>演练需求</strong></p> <ol><li>开发一个 <code>sum_2_num</code> 的函数</li> <li>函数能够实现 <strong>两个数字的求和</strong> 功能</li></ol> <p>演练代码如下：</p> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> <span class="token function">sum_2_num</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">:</span>

    num1 <span class="token operator">=</span> <span class="token number">10</span>
    num2 <span class="token operator">=</span> <span class="token number">20</span>
    result <span class="token operator">=</span> num1 <span class="token operator">+</span> num2

    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;%d + %d = %d&quot;</span> <span class="token operator">%</span> <span class="token punctuation">(</span>num1<span class="token punctuation">,</span> num2<span class="token punctuation">,</span> result<span class="token punctuation">)</span><span class="token punctuation">)</span>

sum_2_num<span class="token punctuation">(</span><span class="token punctuation">)</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><p><strong>思考一下存在什么问题</strong></p> <blockquote><p>函数只能处理 <strong>固定数值</strong> 的相加</p></blockquote> <p><strong>如何解决？</strong></p> <ul><li>如果能够把需要计算的数字，在调用函数时，传递到函数内部就好了！</li></ul> <h3 id="_3-1-函数参数的使用"><a href="#_3-1-函数参数的使用" class="header-anchor">#</a> 3.1 函数参数的使用</h3> <ul><li>在函数名的后面的小括号内部填写 <strong>参数</strong></li> <li>多个参数之间使用 <code>,</code> 分隔</li></ul> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> <span class="token function">sum_2_num</span><span class="token punctuation">(</span>num1<span class="token punctuation">,</span> num2<span class="token punctuation">)</span><span class="token punctuation">:</span>

    result <span class="token operator">=</span> num1 <span class="token operator">+</span> num2
    
    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;%d + %d = %d&quot;</span> <span class="token operator">%</span> <span class="token punctuation">(</span>num1<span class="token punctuation">,</span> num2<span class="token punctuation">,</span> result<span class="token punctuation">)</span><span class="token punctuation">)</span>

sum_2_num<span class="token punctuation">(</span><span class="token number">50</span><span class="token punctuation">,</span> <span class="token number">20</span><span class="token punctuation">)</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br></div></div><h3 id="_3-2-参数的作用"><a href="#_3-2-参数的作用" class="header-anchor">#</a> 3.2 参数的作用</h3> <ul><li><strong>函数</strong>，把 <strong>具有独立功能的代码块</strong> 组织为一个小模块，在需要的时候 <strong>调用</strong></li> <li><strong>函数的参数</strong>，增加函数的 <strong>通用性</strong>，针对 <strong>相同的数据处理逻辑</strong>，能够 <strong>适应更多的数据</strong> <ol><li>在函数 <strong>内部</strong>，把参数当做 <strong>变量</strong> 使用，进行需要的数据处理</li> <li>函数调用时，按照函数定义的<strong>参数顺序</strong>，把 <strong>希望在函数内部处理的数据</strong>，<strong>通过参数</strong> 传递</li></ol></li></ul> <h3 id="_3-3-形参和实参"><a href="#_3-3-形参和实参" class="header-anchor">#</a> 3.3 形参和实参</h3> <ul><li><strong>形参</strong>：<strong>定义</strong> 函数时，小括号中的参数，是用来接收参数用的，在函数内部 <strong>作为变量使用</strong></li> <li><strong>实参</strong>：<strong>调用</strong> 函数时，小括号中的参数，是用来把数据传递到 <strong>函数内部</strong> 用的</li></ul> <h2 id="_04-函数的返回值"><a href="#_04-函数的返回值" class="header-anchor">#</a> 04. 函数的返回值</h2> <ul><li>在程序开发中，有时候，会希望 <strong>一个函数执行结束后，告诉调用者一个结果</strong>，以便调用者针对具体的结果做后续的处理</li> <li><strong>返回值</strong> 是函数 <strong>完成工作</strong>后，<strong>最后</strong> 给调用者的 <strong>一个结果</strong></li> <li>在函数中使用 <code>return</code> 关键字可以返回结果</li> <li>调用函数一方，可以 <strong>使用变量</strong> 来 <strong>接收</strong> 函数的返回结果</li></ul> <blockquote><p>注意：<code>return</code> 表示返回，后续的代码都不会被执行</p></blockquote> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> <span class="token function">sum_2_num</span><span class="token punctuation">(</span>num1<span class="token punctuation">,</span> num2<span class="token punctuation">)</span><span class="token punctuation">:</span>
    <span class="token triple-quoted-string string">&quot;&quot;&quot;对两个数字的求和&quot;&quot;&quot;</span>

    <span class="token keyword">return</span> num1 <span class="token operator">+</span> num2

<span class="token comment"># 调用函数，并使用 result 变量接收计算结果</span>
result <span class="token operator">=</span> sum_2_num<span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">,</span> <span class="token number">20</span><span class="token punctuation">)</span>

<span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;计算结果是 %d&quot;</span> <span class="token operator">%</span> result<span class="token punctuation">)</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br></div></div><h2 id="_05-函数的嵌套调用"><a href="#_05-函数的嵌套调用" class="header-anchor">#</a> 05. 函数的嵌套调用</h2> <ul><li>一个函数里面 <strong>又调用</strong> 了 <strong>另外一个函数</strong>，这就是 <strong>函数嵌套调用</strong></li> <li>如果函数 <code>test2</code> 中，调用了另外一个函数 <code>test1</code> <ul><li>那么执行到调用 <code>test1</code> 函数时，会先把函数 <code>test1</code> 中的任务都执行完</li> <li>才会回到 <code>test2</code> 中调用函数 <code>test1</code> 的位置，继续执行后续的代码</li></ul></li></ul> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> <span class="token function">test1</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">:</span>

    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;*&quot;</span> <span class="token operator">*</span> <span class="token number">50</span><span class="token punctuation">)</span>
    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;test 1&quot;</span><span class="token punctuation">)</span>
    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;*&quot;</span> <span class="token operator">*</span> <span class="token number">50</span><span class="token punctuation">)</span>


<span class="token keyword">def</span> <span class="token function">test2</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">:</span>

    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;-&quot;</span> <span class="token operator">*</span> <span class="token number">50</span><span class="token punctuation">)</span>
    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;test 2&quot;</span><span class="token punctuation">)</span>
    
    test1<span class="token punctuation">(</span><span class="token punctuation">)</span>
    
    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;-&quot;</span> <span class="token operator">*</span> <span class="token number">50</span><span class="token punctuation">)</span>

test2<span class="token punctuation">(</span><span class="token punctuation">)</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br></div></div><h3 id="函数嵌套的演练-打印分隔线"><a href="#函数嵌套的演练-打印分隔线" class="header-anchor">#</a> 函数嵌套的演练 —— 打印分隔线</h3> <blockquote><p>体会一下工作中 <strong>需求是多变</strong> 的</p></blockquote> <p><strong>需求 1</strong></p> <ul><li>定义一个 <code>print_line</code> 函数能够打印 <code>*</code> 组成的 <strong>一条分隔线</strong></li></ul> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> <span class="token function">print_line</span><span class="token punctuation">(</span>char<span class="token punctuation">)</span><span class="token punctuation">:</span>

    <span class="token keyword">print</span><span class="token punctuation">(</span><span class="token string">&quot;*&quot;</span> <span class="token operator">*</span> <span class="token number">50</span><span class="token punctuation">)</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br></div></div><p><strong>需求 2</strong></p> <ul><li>定义一个函数能够打印 <strong>由任意字符组成</strong> 的分隔线</li></ul> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> <span class="token function">print_line</span><span class="token punctuation">(</span>char<span class="token punctuation">)</span><span class="token punctuation">:</span>

    <span class="token keyword">print</span><span class="token punctuation">(</span>char <span class="token operator">*</span> <span class="token number">50</span><span class="token punctuation">)</span>
    
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br></div></div><p><strong>需求 3</strong></p> <ul><li>定义一个函数能够打印 <strong>任意重复次数</strong> 的分隔线</li></ul> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> <span class="token function">print_line</span><span class="token punctuation">(</span>char<span class="token punctuation">,</span> times<span class="token punctuation">)</span><span class="token punctuation">:</span>

    <span class="token keyword">print</span><span class="token punctuation">(</span>char <span class="token operator">*</span> times<span class="token punctuation">)</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br></div></div><p><strong>需求 4</strong></p> <ul><li>定义一个函数能够打印 <strong>5 行</strong> 的分隔线，分隔线要求符合<strong>需求 3</strong></li></ul> <blockquote><p>提示：工作中针对需求的变化，应该冷静思考，<strong>不要轻易修改之前已经完成的，能够正常执行的函数</strong>！</p></blockquote> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">def</span> <span class="token function">print_line</span><span class="token punctuation">(</span>char<span class="token punctuation">,</span> times<span class="token punctuation">)</span><span class="token punctuation">:</span>

    <span class="token keyword">print</span><span class="token punctuation">(</span>char <span class="token operator">*</span> times<span class="token punctuation">)</span>


<span class="token keyword">def</span> <span class="token function">print_lines</span><span class="token punctuation">(</span>char<span class="token punctuation">,</span> times<span class="token punctuation">)</span><span class="token punctuation">:</span>

    row <span class="token operator">=</span> <span class="token number">0</span>
    
    <span class="token keyword">while</span> row <span class="token operator">&lt;</span> <span class="token number">5</span><span class="token punctuation">:</span>
        print_line<span class="token punctuation">(</span>char<span class="token punctuation">,</span> times<span class="token punctuation">)</span>

        row <span class="token operator">+=</span> <span class="token number">1</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br></div></div><h2 id="_06-使用模块中的函数"><a href="#_06-使用模块中的函数" class="header-anchor">#</a> 06. 使用模块中的函数</h2> <blockquote><p><strong>模块是 Python 程序架构的一个核心概念</strong></p></blockquote> <ul><li><strong>模块</strong> 就好比是 <strong>工具包</strong>，要想使用这个工具包中的工具，就需要 <strong>导入 import</strong> 这个模块</li> <li>每一个以扩展名 <code>py</code> 结尾的 <code>Python</code> 源代码文件都是一个 <strong>模块</strong></li> <li>在模块中定义的 <strong>全局变量</strong> 、 <strong>函数</strong> 都是模块能够提供给外界直接使用的工具</li></ul> <h3 id="_6-1-第一个模块体验"><a href="#_6-1-第一个模块体验" class="header-anchor">#</a> 6.1 第一个模块体验</h3> <p><strong>步骤</strong></p> <ul><li>新建 <code>hm_10_分隔线模块.py</code> <ul><li>复制 <code>hm_09_打印多条分隔线.py</code> 中的内容，<strong>最后一行 <code>print</code> 代码除外</strong></li> <li>增加一个字符串变量</li></ul></li></ul> <div class="language-python line-numbers-mode"><pre class="language-python"><code>name <span class="token operator">=</span> <span class="token string">&quot;黑马程序员&quot;</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div><ul><li>新建 <code>hm_10_体验模块.py</code> 文件，并且编写以下代码：</li></ul> <div class="language-python line-numbers-mode"><pre class="language-python"><code><span class="token keyword">import</span> hm_10_分隔线模块

hm_10_分隔线模块<span class="token punctuation">.</span>print_line<span class="token punctuation">(</span><span class="token string">&quot;-&quot;</span><span class="token punctuation">,</span> <span class="token number">80</span><span class="token punctuation">)</span>
<span class="token keyword">print</span><span class="token punctuation">(</span>hm_10_分隔线模块<span class="token punctuation">.</span>name<span class="token punctuation">)</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br></div></div><h4 id="体验小结"><a href="#体验小结" class="header-anchor">#</a> 体验小结</h4> <ul><li>可以 <strong>在一个 Python 文件</strong> 中 <strong>定义 变量 或者 函数</strong></li> <li>然后在 <strong>另外一个文件中</strong> 使用 <code>import</code> 导入这个模块</li> <li>导入之后，就可以使用 <code>模块名.变量</code> / <code>模块名.函数</code> 的方式，使用这个模块中定义的变量或者函数</li></ul> <blockquote><p><strong>模块</strong>可以让 <strong>曾经编写过的代码</strong> 方便的被 <strong>复用</strong>！</p></blockquote> <h3 id="_6-2-模块名也是一个标识符"><a href="#_6-2-模块名也是一个标识符" class="header-anchor">#</a> 6.2 模块名也是一个标识符</h3> <ul><li>标示符可以由 <strong>字母</strong>、<strong>下划线</strong> 和 <strong>数字</strong> 组成</li> <li><strong>不能以数字开头</strong></li> <li><strong>不能与关键字重名</strong></li></ul> <blockquote><p>注意：如果在给 Python 文件起名时，<strong>以数字开头</strong> 是无法在 <code>PyCharm</code> 中通过导入这个模块的</p></blockquote> <h3 id="_6-3-pyc-文件-了解"><a href="#_6-3-pyc-文件-了解" class="header-anchor">#</a> 6.3 Pyc 文件（了解）</h3> <blockquote><p><code>C</code> 是 <code>compiled</code> <strong>编译过</strong> 的意思</p></blockquote> <p><strong>操作步骤</strong></p> <ol><li>浏览程序目录会发现一个 <code>__pycache__</code> 的目录</li> <li>目录下会有一个 <code>hm_10_分隔线模块.cpython-35.pyc</code> 文件，<code>cpython-35</code> 表示 <code>Python</code> 解释器的版本</li> <li>这个 <code>pyc</code> 文件是由 Python 解释器将 <strong>模块的源码</strong> 转换为 <strong>字节码</strong> <ul><li><code>Python</code> 这样保存 <strong>字节码</strong> 是作为一种启动 <strong>速度的优化</strong></li></ul></li></ol> <p><strong>字节码</strong></p> <ul><li><p><code>Python</code> 在解释源程序时是分成两个步骤的</p> <ol><li>首先处理源代码，<strong>编译</strong> 生成一个二进制 <strong>字节码</strong></li> <li>再对 <strong>字节码</strong> 进行处理，才会生成 CPU 能够识别的 <strong>机器码</strong></li></ol></li> <li><p>有了模块的字节码文件之后，下一次运行程序时，如果在 <strong>上次保存字节码之后</strong> 没有修改过源代码，Python 将会加载 .pyc 文件并跳过编译这个步骤</p></li> <li><p>当 <code>Python</code> 重编译时，它会自动检查源文件和字节码文件的时间戳</p></li> <li><p>如果你又修改了源代码，下次程序运行时，字节码将自动重新创建</p></li></ul> <blockquote><p>提示：有关模块以及模块的其他导入方式，后续课程还会逐渐展开！</p> <p><strong>模块是 Python 程序架构的一个核心概念</strong></p></blockquote></div></div> <!----> <div class="page-edit"><div class="edit-link"><a href="https://github.com/xugaoyi/vuepress-theme-vdoing/edit/master/docs/00.Python/13.函数基础.md" target="_blank" rel="noopener noreferrer">编辑</a> <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></div> <!----> <!----></div> <div class="page-nav-wapper"><div class="page-nav-centre-wrap"><a href="/vdoing-demo-repository/pages/3ce888/" class="page-nav-centre page-nav-centre-prev"><div class="tooltip">12_循环</div></a> <a href="/vdoing-demo-repository/pages/e158a8/" class="page-nav-centre page-nav-centre-next"><div class="tooltip">14_高级变量类型</div></a></div> <div class="page-nav"><p class="inner"><span class="prev">
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